AE Presets: Smooth Vertical Scrolls for TV

UPDATE: The presets now come in both PAL and NTSC variants, and include a flicker-reducing filter that adjusts itself to the chosen speed.

Working at a TV station, I see so many jumpy titles that were created in After Effects. This comes from the fact that interlaced video gives a sort of venetian blinds effect to your content, making vertical scrolls flicker if you don't scroll at certain fixed speeds.

In version 6.5, it was easy to tell people to set two keyframes and then just move the last keyframe so that the pixels/sec velocity read-out was an even double of the framerate. This was a useful feature that was actually removed when the Graph Editor was introduced in version 7.0, since you can't see this value until you release the keyframe.

When I got the question the last time I couldn't find where to enter the value anymore, making me feel kinda stupid. In a vain attempt to look like I was on top of things, I came up with the simple and unsofisticated solution of three Animation Presets for the three common scrolling speeds.

The layer that you apply the preset to will start to scroll upwards from its original position as soon as it appears in the timeline. The nice thing is that you can just drag it around to set the starting position, without having to modify any code.

//Smooth SD vertical scrolls by Jonas Hummelstrand
// Version 1.3, http://generalspecialist.com/
// Can be applied to a non-square NTSC comps or to both square and
// non-square PAL comps.

// Change the value of "intPixelsPerSecond" below based on the speed you want:
// Normal scrolls are 100 for PAL and 119.88 for NTSC
// Fast scrolls are 200 for PAL and 239.76 for NTSC
// American Idol scroll speeds are 300 for PAL and 359.64 for NTSC

intPixelsPerSecond = 100;

y=position[1]-((time-inPoint)*intPixelsPerSecond);
[position[0],y]

Here's a ZIP file with the three PAL and three NTSC speeds pre-configured.

Thanks to Nathan Shipley for the error-correction.